The present invention relates to propene terpolymers consisting of from 80 to 99.5 mol % of structural units derived from propene, from 0.1 to 15 mol % of structural units derived from ethene or a C4-C6-1-olefin (I) and from 0.1 to 15 mol % of structural units derived from a further C4-C12-1-olefin (II) which is different from the C4-C6-1-olefin (I), which propene terpolymers have a proportion of regioregular xe2x80x21-2xe2x80x2-inserted propene units corresponding to the formula (1)                                           [            xe2x80x2                    ⁢                      1            -                          2              xe2x80x2                                ]                                                    [              xe2x80x2                        ⁢                          1              -                              2                xe2x80x2                                      ]                    +                                    [              xe2x80x2                        ⁢                          2              -                              1                xe2x80x2                                      ]                    +                                    [              xe2x80x2                        ⁢                          1              -                              3                xe2x80x2                                      ]                                              (        1        )            
of more than 0.99, have a melting point (TM), determined from the DSC peak maximum, of less than 135xc2x0 C. and a weight average molecular weight (MW) of more than 80,000 g/mol and have a xylene-soluble proportion (XS) in % by weight of the propene terpolymer which obeys the following inequality (2)
XSxe2x89xa61411.21 exp(xe2x88x920.0591 TM[xc2x0 C.])xe2x88x920.05xe2x80x83xe2x80x83(2).
The present invention further relates to a process for preparing propene terpolymers, their use for preparing films, fibers and moldings, the films, fibers and moldings obtainable in this way and also heat-sealable coating materials obtainable therefrom.
Binary copolymers of propene with ethene or a higher 1-olefin as comonomer prepared by means of metallocene catalysts are, inter alia, very suitable as materials for heat-sealable coatings (EP-A 668 157, DE-A 19 533 337). Compared to heat-sealable coating materials prepared using conventional Ziegler-Natta catalysts, the binary copolymers of propene prepared using metallocene catalysts have a very regular comonomer incorporation independent of the degree of polymerization, which results in them having comparatively low extractables contents. At the same time, such binary copolymers of propene are, even at low melting points, less sticky than heat-sealable coating materials which are obtained using conventional Ziegler Natta catalysts, which is why the preparation of binary copolymers of propene having a relatively low melting point is possible even under industrial conditions. This is advantageous because a low melting point usually allows lower heat-sealing temperatures which enables the cycle times in the heat-sealing process to be reduced. However, even in the case of the binary copolymers of propene prepared using metallocene catalysts, the extractables content is found to increase with decreasing melting point. As a consequence, binary copolymers of propene having a relatively low melting point can be used only to a limited extent in certain applications, for example as heat-sealable coating materials in the food sector, because the extractables content is too high.
EP-A 685 498 discloses propene terpolymers which are prepared by means of metallocene catalysts in which simple metallocenes without substituents in the xcex1 position to the bridge of the metallocene complex are used. Such propene terpolymers have a proportion of regioirregular propene units of more than 1% [T. Tsutsui et al., J. Mol. Catalysis 56, 237 (1989)]. In addition, the proportion of extractables, for example material which can be extracted in boiling pentane, in these propene terpolymers is still rather too high for some applications.
Furthermore, DE-A 4 317 654 describes terpolymers of propene with copolymerized ethene and 1-butene, where the polymerization is carried out using a supported metallocene catalyst comprising a metallocene complex having xcex1 substituents which is activated by means of a mixture of two different aluminoxanes. Such terpolymers of propene likewise have extractables contents which are still capable of improvement for some applications.
It is an object of the present invention to remedy the abovementioned drawbacks and to provide terpolymers of propene whose extractables content is further reduced, which have a low melting point and a sufficiently high molecular weight for the production of films and can be used without any great changes in existing industrial processes for producing heat-sealable coating materials.
We have found that this object is achieved by the propene terpolymers defined at the outset.
We have also found a process for preparing the propene terpolymers of the invention and also their use for producing films, fibers and moldings. The present invention also extends to films, fibers and moldings and to heat-sealable coating materials comprising the propene terpolymers of the present invention.
The propene terpolymers of the present invention consist of from 80 to 99.5 mol % of structural units derived from propene, preferably from 85 to 99 mol %, in particular from 87 to 98 mol %, also from 0.1 to 15 mol % of structural units derived from ethene or a C4-C6-1-olefin (I), preferably from 0.5 to 13 mol %, in particular from 0.5 to 10 mol %, plus from 0.1 to 15 mol % of structural units derived from a further C4-C12-1-olefin (II) which is different from the C4-C6-1-olefin (I), preferably from 0.3 to 12 mol %, in particular from 0.3 to 10 mol %. The sum of the mol % is always 100.
Suitable C4-C6-1-olefins (I) are, for example, 1-butene, 1-pentene, 4-methyl-1-pentene or 1-hexene, with preference being given to using 1-butene, 1-pentene or 1-hexene.
Suitable C4-C12-1-olefins (II) are, in particular, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene or 1-octene with particular preference being given to using 1-butene, 1-pentene and 1-hexene.
Particularly preferred propene terpolymers contain from 0.1 to 15 mol %, preferably from 0.1 to 10 mol %, of structural units derived from ethene, 1-pentene or 1-hexene and from 0.1 to 15 mol %, preferably from 0.1 to 8 mol %, of structural units derived from 1-butene.
The melting point (TM) of the propene terpolymers of the present invention, determined from the DSC peak maximum, is less than 135xc2x0 C., in particular less than 130xc2x0 C.
The propene terpolymers of the present invention also have a weight average molecular weight (MW) of more than 80,000 g/mol, in particular more than 150,000 g/mol. The weight average molecular weight (MW) is determined by gel permeation chromatography (GPC).
Furthermore, the propene terpolymers of the present invention have a proportion of regioregular xe2x80x21-2xe2x80x2-inserted propene units corresponding to the formula (1)                                           [            xe2x80x2                    ⁢                      1            -                          2              xe2x80x2                                ]                                                    [              xe2x80x2                        ⁢                          1              -                              2                xe2x80x2                                      ]                    +                                    [              xe2x80x2                        ⁢                          2              -                              1                xe2x80x2                                      ]                    +                                    [              xe2x80x2                        ⁢                          1              -                              3                xe2x80x2                                      ]                                              (        1        )            
of more than 0.99. The regioregular xe2x80x21-2xe2x80x2-insertion of propene, the regioirregular xe2x80x22-1xe2x80x2-insertion and the likewise regioirregular xe2x80x21-3xe2x80x2-insertion are known, for example, from P. Pino et al., Angew. Chemie 92, 869 (1980) or from A. Zambelli et al., Macromolecules 21, 617 (1988).
The determination of the respective proportions of the regioregular xe2x80x21-2xe2x80x2-insertion, the regioirregular xe2x80x22-1xe2x80x2-insertion and the regioirregular xe2x80x21-3xe2x80x2-insertion is carried out, for example, by 13C-NMR spectroscopy as described in A. Zambelli et al., Macromolecules 21, 617 (1988).
The amount of xylene-soluble material (XS) in the propene terpolymer of the present invention, in percent by weight, obeys the following inequality (2)
XSxe2x89xa61411.21 exp(xe2x88x920.591 TM[xc2x0 C.])xe2x88x920.05xe2x80x83xe2x80x83(2)
where TM is the melting point of the propene terpolymer in xc2x0 C.
In addition, preferred propene terpolymers of the present invention have a polydispersity (Mw/Mn) of less than 2.25, especially less than 2.1 and in particular less than 2.0. The determination of the polydispersity (Mw/Mn) is preferably carried out by means of gel permeation chromatography using 1,2,4-trichlorobenzene as solvent.
The propene terpolymers of the present invention are preferably prepared by a likewise novel process which comprises polymerizing the comonomers in the presence of a metallocene catalyst system comprising
A) an inorganic or organic support,
B) at least one metallocene complex and
C) at least one compound capable of forming metallocenium ions, where, however, component C) does not comprise two different aluminoxanes.
The metallocene catalyst system used in the likewise novel process can further comprise, in addition to the components A), B) and C), at least one organic metal compound of an alkali metal or alkaline earth metal or a metal of main group III of the Periodic Table.
The polymerization for preparing the propene terpolymers of the present invention by means of such metallocene catalyst systems is carried out at from xe2x88x9250 to 300xc2x0 C., preferably from 0 to 150xc2x0 C., and at pressures of from 0.5 to 3000 bar, preferably from 1 to 100 bar. In this likewise novel process, the residence times of the respective reaction mixtures should be set to from 0.5 to 5 hours, in particular from 0.7 to 3.5 hours. In the polymerization, it is also possible to make concomitant use of, inter alia, antistatics and molecular weight regulators, for example hydrogen.
The polymerization can be carried out in solution, in suspension, in liquid monomers or in the gas phase. The polymerization is preferably carried out in liquid monomers (bulk process) or in the gas phase, with preference being given to the stirred gas phase.
The likewise novel process can be carried out either continuously or batchwise. Suitable reactors are, inter alia, continuous stirred tank reactors or loop reactors; it is also possible, if desired, to use a plurality of stirred tank reactors or loop reactors connected in series (reactor cascade).
The metallocene catalyst systems used comprise an inorganic or organic support as component A). As inorganic support, it is possible to use an inorganic oxide which has a pH determined by the method of S. R. Morrison, xe2x80x9cThe Chemical Physics of Surfacesxe2x80x9d, Plenum Press, New York [1977], pages 130ff, of from 1 to 6 and has voids and channels whose macroscopic proportion by volume in the total particle is in the range from 5 to 30%. Particular preference is given to using inorganic oxides whose pH, i.e. the negative logarithm to the base 10 of the proton concentration, is in the range from 2 to 5.5.
As inorganic supports, particular preference is given to inorganic oxides which have a mean particle diameter of from 5 to 200 xcexcm, in particular from 20 to 90 xcexcm, and a mean particle diameter of the primary particles of from 0.1 to 20 xcexcm, in particular from 0.1 to 5 xcexcm. The primary particles here are porous, granular particles. The primary particles have pores having a diameter of, in particular, from 0.1 to 1000 xc3x85. Furthermore, the inorganic oxides to be used have voids and channels having a mean diameter of from 0.1 to 20 xcexcm, in particular from 1 to 15 xcexcm. In particular, the inorganic oxides also have a pore volume of from 0.1 to 10 cm3/g, preferably from 1.0 to 5.0 cm3/g, and a specific surface area of from 10 to 1000 m2/g, preferably from 100 to 500 m2/g. Such finely divided inorganic oxides are obtainable, for example, by spray drying milled hydrogels and are also commercially available.
Preferred inorganic supports are, in particular, oxides of silicon, of aluminum, of titanium or of a metal of main group I or II of the Periodic Table. Particularly preferred inorganic oxides are aluminum oxide, magnesium oxide, sheet silicates and also silica gel (SiO2).
It is also possible to use cogels, i.e. mixtures of at least two different inorganic oxides, as component A).
Furthermore, the catalyst component A) can also be an organic support, for example a thermoplastic polymer. Preferred organic supports are polymers of 1-alkenes, in particular propene homopolymers or propene copolymers, also ethene homopolymers or ethene copolymers. It is also possible to use polymers of styrene.
Preference is given to using from 0.1 to 10,000 xcexcmol, in particular from 5 to 200 xcexcmol, of the metallocene complex, i.e. the component B), per gram of support, i.e. the component A).
As component B), the metallocene catalyst system used comprises one or more metallocene complexes. Particularly suitable metallocene complexes are those of the formula (I) 
where the substituents have the following meanings:
M is titanium, zirconium, hafnium, vanadium, niobium or tantalum, or an element of transition group III of the Periodic Table and the lanthanides,
X is fluorine, chlorine, bromine, iodine, hydrogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical, xe2x80x94OR10 or xe2x80x94NR10R11,
n is an integer from 1 to 3, where n corresponds to the valence of M minus 2,
xe2x80x83where
R10 and R11 are C1-C10-alkyl, C6-C15-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical,
R5 to R9 are hydrogen, C1-C10-alkyl, 5- to 7-membered cycloalkyl which may in turn bear a C1-C10-alkyl group as substituent, C6-C15-aryl or arylalkyl, where two adjacent radicals may also together be a saturated or unsaturated cyclic group having from 4 to 15 carbon atoms which may in turn bear a C1-C8-alkyl radical, a C7-C20-arylalkyl radical or a C6-C10-aryl radical as substituent, or Si(R12)3 where
R12 is C1-C10-alkyl, C3-C10-cycloalkyl or C6-C15-aryl,
Z is X or 
xe2x80x83where the radicals
R13 to R17 are hydrogen, C1-C10-alkyl, 5- to 7-membered cycloalkyl which may in turn bear a C1-C10-alkyl group as substituent, C6-C15-aryl or arylalkyl, where two adjacent radicals may also together be a saturated or unsaturated cyclic group having from 4 to 15 carbon atoms, which may in turn bear a C1-C8-alkyl radical, a C6-C10-aryl radical or a C7-C20-arylalkyl radical as substituent, or Si(R18)3 where
R18 is C1-C10-alkyl, C6-C15-aryl or C3-C10-cycloalkyl,
or the radicals R8 and Z together form an xe2x80x94R19xe2x80x94Axe2x80x94 group, where 
xe2x95x90BR20, xe2x95x90AlR20, xe2x80x94Gexe2x80x94, xe2x80x94Snxe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x95x90SO, xe2x95x90SO2, xe2x95x90NR20, xe2x95x90CO, xe2x95x90PR20 or xe2x95x90P(O)R20,
xe2x80x83where
R20, R21 and R22 are identical or different and are each a hydrogen atom, a halogen atom, a C1-C10-alkyl group, a C1-C10-fluoroalkyl group, a C6-C10-fluoroaryl group, a C6-C10-aryl group, a C1-C10-alkoxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C8-C40-arylalkenyl group or a C7-C40-alkylaryl group or two adjacent radicals in each case together with the atoms connecting them form a ring, and
M2 is silicon, germanium or tin,
A is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, 
xe2x80x83where
R23 is C1-C10-alkyl, C6-C15-aryl, C3-C10-cycloalkyl, alkylaryl or Si(R24)3, where
R24 is hydrogen, C1-C10-alkyl, C6-C15-aryl, which may in turn bear C1-C4-alkyl groups as substituents or C3-C10-cycloalkyl
or the radicals R8 and R16 together form an xe2x80x94R19xe2x80x94 group.
Among the metallocene complexes of the formula I, preference is given to 
The radicals X can be identical or different, but are preferably identical.
Among the compounds of the formula Ia, particular preference is given to those in which
M is titanium, zirconium or hafnium,
X is chlorine, C1-C4-alkyl or phenyl,
n is 2 and
R5 to R9 are hydrogen or C1-C4-alkyl.
Among the compounds of the formula Ib, preference is given to those in which
M is titanium, zirconium or hafnium,
X is chlorine, C1-C4-alkyl or phenyl,
n is 2,
R5 to R9 are hydrogen, C1-C4-alkyl or Si(R12)3,
R13 to R17 are hydrogen, C1-C4-alkyl or Si(R18)3.
Particularly suitable compounds of the formula Ib are those in which the cyclopentadienyl radicals are identical.
Examples of particularly suitable compounds are: bis(cyclopentadienyl)zirconium dichloride, bis(pentamethylcyclopentadienyl)zirconium dichloride, bis(methylcyclopentadienyl)zirconium dichloride, bis(ethylcyclopentadienyl)zirconium dichloride, bis(n-butylcyclopentadienyl)zirconium dichloride and bis(trimethylsilylcyclopentadienyl)zirconium dichloride and also the corresponding dimethylzirconium compounds.
Particularly suitable compounds of the formula Ic are those in which
R5 and R13 are identical and are hydrogen or C1-C10-alkyl,
R9 and R17 are identical and are hydrogen, methyl, ethyl, isopropyl or tert-butyl,
R6, R7, R14 and R15 have the meanings R7 and R15 are C1-C4-alkyl, R6 and R14 are hydrogen or two adjacent radicals R6 and R7 or R14 and R15 are together a cyclic group having from 4 to 18 carbon atoms, 
M is titanium, zirconium or hafnium and
X is chlorine, C1-C4-alkyl or phenyl.
Examples of particularly suitable complexes are: dimethylsilanediylbis(cyclopentadienyl)zirconium dichloride, dimethylsilanediylbis(indenyl)zirconium dichloride, dimethylsilanediylbis(tetrahydroindenyl)zirconium dichloride, ethylenebis(cyclopentadienyl)zirconium dichloride, ethylenebis(indenyl)zirconium dichloride, ethylenebis(tetrahydroindenyl)zirconium dichloride, tetramethylethylene-9-fluorenylcyclopentadienylzirconium dichloride, dimethylsilanediylbis(3-tert-butyl-5-methylcyclopentadienyl)zirconium dichloride, dimethylsilanediylbis(3-tert-butyl-5-ethylcyclopentadienyl)zirconium dichloride, dimethylsilanediylbis(2-methylindenyl)zirconium dichloride, dimethylsilanediylbis(2-isopropylindenyl)zirconium dichloride, dimethylsilanediylbis(2-tert-butylindenyl)zirconium dichloride, diethylsilanediylbis(2-methylindenyl)zirconium dibromide, dimethylsilanediylbis(3-methyl-5-methylcyclopentadienyl)zirconium dichloride, dimethylsilanediylbis(3-ethyl-5-isopropylcyclopentadienyl)zirconium dichloride, dimethylsilanediylbis(2-ethylindenyl)zirconium dichloride, dimethylsilanediylbis(2-methylbenzindenyl)zirconium dichloride, dimethylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride, methylphenylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride, methylphenylsilanediylbis(2-methylbenzindenyl)zirconium dichloride, diphenylsilanediylbis(2-methylbenzindenyl)zirconium dichloride, diphenylsilanediylbis(2-ethylbenzindenyl)zirconium dichloride, diphenylsilanediylbis(2-methylindenyl)hafnium dichloride and also the corresponding dimethylzirconium compounds.
Further examples of suitable complexes are: dimethylsilanediylbis(2-methyl-4-phenylindenyl)zirconium dichloride, dimethylsilanediylbis(2-methyl-4-naphthylindenyl)zirconium dichloride, dimethylsilanediylbis(2-methyl-4-isopropylindenyl)zirconium dichloride, dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)zirconium dichloride and also the corresponding dimethylzirconium compounds.
Particularly useful compounds of the formula Id are those in which
M is titanium or zirconium,
X is chlorine, C1-C4-alkyl or phenyl, 
and
R5 to R7 and R9 are hydrogen, C1-C10-alkyl, C3-C10-cycloalkyl, C6-C15-aryl or Si(R12)3 or two adjacent radicals are a cyclic group having from 4 to 12 carbon atoms.
Such complexes can be synthesized by methods known per se, with preference being given to reacting the appropriately substituted, cyclic hydrocarbon anions with halides of titanium, zirconium, hafnium, vanadium, niobium or tantalum.
Examples of appropriate preparative methods are described, inter alia, in Journal of Organometallic Chemistry, 369 (1989), 359-370.
It is also possible to use mixtures of different metallocene complexes.
As component C), the metallocene catalyst system used in the likewise novel process comprises at least one compound capable of forming metallocenium ions, but component C) does not comprise two different aluminoxanes.
Suitable compounds capable of forming metallocenium ions are strong, uncharged Lewis acids, ionic compounds containing Lewis acid cations and ionic compounds containing Brxc3x6nsted acids as cation.
As strong, uncharged Lewis acids, preference is given to compounds of the formula II
M3X1X2X3xe2x80x83xe2x80x83II
where
M3 is an element of main group III of the Periodic Table, in particular B, Al or Ga, preferably B,
X1, X2 and X3 are hydrogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl, arylalkyl, haloalkyl or haloaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical or fluorine, chlorine, bromine or iodine, in particular haloaryls, preferably pentafluorophenyl.
Particular preference is given to compounds of the formula II in which X1, X2 and X3 are identical, preferably tris(pentafluorophenyl)borane.
Useful ionic compounds containing Lewis acid cations are compounds of the formula III
[(Ya+)Q1Q2 . . . Qz]d+xe2x80x83xe2x80x83III
where
Y is an element of main groups I to VI or transition groups I to VIII of the Periodic Table,
Q1 to Qz are singly negatively charged groups such as C1-C28-alkyl, C6-C15-aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl each having from 6 to 20 carbon atoms in the aryl part and from 1 to 28 carbon atoms in the alkyl part, C3-C10-cycloalkyl, which may bear C1-C10-alkyl groups as substituents, halogen, C1-C28-alkoxy, C6-C15-aryloxy, silyl or mercaptyl groups,
a is an integer from 1 to 6 and
z is an integer from 0 to 5, and
d corresponds to the difference axe2x88x92z, with the proviso that d is greater than or equal to 1.
Particularly suitable Lewis acid cations are carbonium cations, oxonium cations and sulfonium cations and also cationic transition metal complexes. Particular mention may be made of the triphenylmethyl cation, the silver cation and the 1,1xe2x80x2-dimethylferrocenyl cation. They preferably have non coordinating counterions, in particular boron compounds as are also mentioned in WO-A 91/09882, preferably tetrakis(pentafluorophenyl)borate.
Ionic compounds containing Brxc3x6nsted acids as cations and preferably likewise non coordinating counterions are mentioned in WO-A 91/09882; the preferred cation is N,N-dimethylanilinium.
The compound C) capable of forming metallocenium ions is preferably used in an amount of from 0.1 to 10 equivalents, based on the metallocene complex I.
Particularly suitable compounds C) capable of forming metallocenium ions are open-chain or cyclic aluminoxane compounds of the formula IV or V 
where R4 is a C1-C4-alkyl group, preferably a methyl or ethyl group, and m is an integer from 5 to 30, preferably from 10 to 25.
The preparation of these oligomeric aluminoxane compounds is usually carried out by reacting a solution of trialkylaluminum with water and is described, for example, in EP-A 284 708 and U.S. Pat. No. 4,794,096.
In general, the oligomeric aluminoxane compounds obtained in this way are in the form of mixtures of both linear and cyclic chain molecules of different lengths, so that m should be regarded as a mean. The aluminoxane compounds can also be present in admixture with other metal alkyls, preferably aluminum alkyls.
In the metallocene catalyst system which is used in the process of the present invention, there are not two different aluminoxanes of the formula IV or V present as compound C) capable of forming metallocenium ions. For the purposes of the present invention, different aluminoxanes are aluminoxanes of the formula IV or V which have different radicals R4.
Preferably, both the metallocene complexes (component B) and the compound capable of forming metallocenium ions (component C) are used in solution; particularly preferred solvents are aromatic hydrocarbons having from 6 to 20 carbon atoms, in particular xylenes and toluene.
Furthermore, it is also possible to use aryloxyaluminoxanes, as described in U.S. Pat. No. 5,391,793, aminoaluminoxanes as described in U.S. Pat. No. 5,371,260, aminoaluminoxane hydrochlorides as described in EP-A 633 264 or siloxyaluminoxanes, as described in EP-A 621 279 as component C).
It has been found to be advantageous to use the metallocene complexes and the oligomeric aluminoxane compound in such amounts that the atomic ratio of aluminum from the oligomeric aluminoxane compound to the transition metal from the metallocene complexes is in the range from 10:1 to 106:1, in particular in the range from 10:1 to 104:1.
The metallocene catalyst system used for preparing the propene terpolymers of the present invention may, if desired, further comprise, as component D), a metal compound of the formula VI
M1(R1)r(R2)s(R3)txe2x80x83xe2x80x83VI
where
M1 is an alkali metal, an alkaline earth metal or a metal of main group III of the Periodic Table, i.e. boron, aluminum, gallium, indium or thallium,
R1 is hydrogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl or arylalkyl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical,
R2 and R3 are hydrogen, halogen, C1-C10-alkyl, C6-C15-aryl, alkylaryl, arylalkyl or alkoxy each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 20 carbon atoms in the aryl radical,
r is an integer from 1 to 3 and
s and t are integers from 0 to 2, where the sum r+s+t corresponds to the valence of M1.
Among the metal compounds of the formula VI, preference is given to those in which
M1 is lithium, magnesium or aluminum and
R1 to R3 are C1-C10-alkyl.
Particularly preferred metal compounds of the formula VI are n-butyllithium, n-butyl-n-octylmagnesium, n-butyl-n-heptylmagnesium, tri-n-hexylaluminum, triisobutylaluminum, triethylaluminum and trimethylaluminum.
If a component D) is used, it is preferably present in the catalyst system in an amount of from 800:1 to 1:1, in particular from 500:1 to 50:1 (molar ratio of M1 from formula VI to transition metal M from formula I).
The components A), B), C) and, if desired, D) are used together as metallocene catalyst system.
The propene terpolymers of the present invention have a very low proportion of extractables together with a low melting point and also a sufficiently high molecular weight for the production of films. They are, inter alia, well suited to the production of heat-sealable coating materials. They are generally well suited to the production of films, fibers and moldings.
The likewise novel process in which the metallocene catalyst systems described are used is relatively simple to carry out and has a high productivity.